1. Field of the Invention
This invention relates, generally, to novel conveyor system accessories for loading and unloading a work piece from a conveyor system. The present invention provides an inexpensive way to stage, stockpile and/or sort work pieces and provides easy entry to and exit from a main conveyor. Alternatively, work pieces may reenter the main conveyor, if desired. Specifically, a trolley or trolleys that carry work pieces ride on the conveyor rail above the chain or intermesh with the chain on the inside of the track. These accessories are used with single track continuous conveyor systems, which greatly enhances the productivity of the single track system by permitting work pieces to be taken off-line without taking the work piece off a load pendant.
2. Description of the Related Art
Conventional overhead trolley carriers are known in the art. One such type is a continuous flow conveyor. The continuous flow conveyor is restricted by a moving chain, which severely limits the utility of this type of conveyor. Specifically, when it is necessary to remove a work piece from the conveyor it is necessary to take it off a load pendant. Generally, the removal of the work piece from the load pendant requires disengagement of the conveyor drive train, thus stopping motion of the conveyor. Alternatively, if complete stoppage of the conveyor is to be avoided, the conveyor must be slowed down considerably to facilitate the removal of the work piece from the load pendant. Both methods of unloading, however, greatly impact the productivity of the conveyor system.
More recently, power and free conveyor systems have been developed to overcome the problems associated with the staging, stockpiling, and/or sorting of work pieces in continuous flow conveyors. Power and free systems have a power track and a carrier track arranged in vertically spaced relation. The power track is an endless chain supported by trolleys mounted on the power track, and longitudinally spaced pushers carried by the chain. A pusher is engageable with a driving dog on the front end of a load carrier, and disengaging means associated with the driving dog is operable by actuating means on the rear end of a preceding load carrier so that successive load carriers can automatically accumulate behind a stopped load carrier. Power and free conveyors overcome many of the problems associated with continuous flow conveyors. These power and free conveyors are, however, generally more than twice as expensive as continuous flow conveyors.
In view of the prior art at the time the present invention was made, it was not obvious to those of ordinary skill in the pertinent art how the needed inexpensive yet efficient staging, stockpiling, and/or sorting conveyor system could be provided.
In accordance with the present invention, a single track continuous conveyor system accessory is provided. In one embodiment of the present invention the conveyor system accessory is a wheel assembly for riding on top of an inverted continuous conveyor track. The wheel assembly has a pair of wheels, which are spaced apart in a parallel side by side relationship and are connected to one another by a transverse axle. A drive means for a conveyor chain is positioned in the inverted continuous conveyor track to engage the wheel assembly and move it in a desired direction. A carrying means for transporting a work piece is rotatably attached to the wheel assembly. The present invention also includes a loading means for positioning the wheel assembly on the top surface of the inverted continuous conveyor track and an unloading means for removing the wheel assembly from the top surface of the inverted continuous conveyor track.
A second wheel assembly is provided for the transport of heavy loads and is used in conjunction with the wheel assembly. In particular, the second wheel assembly has a second pair of wheels, which are spaced apart in a parallel side by side relationship and are connected to one another by a second transverse axle. The second wheel assembly is connected to the wheel assembly by a pair of longitudinal members with one end of each pair of longitudinal members rotatably connected to the transverse axle and an opposite end of each pair of longitudinal members rotatably connected to the second transverse axle. Loading means and unloading means are also provided for positioning and removing the combination of the wheel assembly and second wheel assembly on and from the inverted continuous conveyor track, respectively.
The conveyor system accessory may also include an alignment means for maintaining the wheel assembly and the combination of the wheel assembly and the second wheel assembly on the top surface of the inverted continuous conveyor track. The alignment means is a plate which is fixedly attached to each of the wheels of the pair of wheels of the wheel assembly and the second wheel assembly. The plates are situated on an external surface of each of the wheels, are perpendicular to the transverse axle, and extend beyond each wheel and overlap a portion of both sides of the inverted continuous conveyor track to form a boundary means for maintaining the wheel assembly in combination with the second wheel assembly on the top surface of the inverted continuous conveyor track.
The present system also provides a drive means, which is a vertically oriented elongate planar shaped member that is fixed at one end to the conveyor chain. The opposite end has notches on both sides for engaging the transverse axle of the wheel assembly in combination with the second -transverse axle of the second wheel assembly.
In an alternative embodiment the wheel assembly meshes with the inverted continuous conveyor track. In this embodiment, the wheel assembly defines an inverted V-shaped assembly having a transverse member across an apex of the V-shaped assembly. The transverse member has rollers on either side of the apex for rolling on a ramp. The inverted V-shaped assembly is attached to a housing, which has a pair of wheels at its front end and a pair of wheels at its rear end. The pairs of wheels are spaced apart in a parallel side by side relationship and are connected to the housing. A drive means is positioned in the inverted continuous track and engages the wheel assembly and moves the wheel assembly in a desired direction. A carrying means for transporting a work piece is rotatably attached to the wheel assembly. Loading and unloading means for facilitating the intermeshing and disengagement, respectively, of the wheel assembly are also provided.
The housing of the present invention is an inverted U-shaped assembly with a cut out or slot portion for engagement of the drive means. The inverted U-shaped member allows the respective pairs of wheels of the wheel assembly to straddle a drive portion of the drive means and effectively intermesh with the drive means.
In yet a further embodiment, a wheel assembly for riding on a top surface of an inverted continuous conveyor track has a pair of V-shaped rollers. The V-shaped rollers are spaced apart and aligned to engage the upper most corners of the inverted continuous conveyor track and are fixedly attached to a V-shaped angle member by a transverse axle. A drive means is also provided. The drive means engages the V-shaped angle member and moves the wheel assembly in a desired direction. The wheel assembly has a carrying means for transporting a work piece, which is rotatably attached to the wheel assembly. Loading and unloading means are provided.